The NWS pushes alerts through a few different channels. Most weather apps pull from the public REST API at api.weather.gov, which typically adds a 60–120 second delay between issuance and delivery.
StormSync VT/OI connects directly to the NOAA Weather Wire Service Open Interface (NWWS-OI) — an authenticated XMPP feed that TV and radio broadcasters, emergency managers, and commercial alerting services rely on. Alerts arrive within seconds of issuance, often before most other systems have even received them.
This is the same feed that fires off the Emergency Alert System on broadcast TV. StormSync makes it available as a free desktop application.
While running, StormSync holds a persistent XMPP connection open to NWS servers. Every text product from any Weather Forecast Office or National Center is delivered straight to your machine as it's issued.
Each product is parsed for VTEC codes, UGC zones, phenomena type, and severity. Tornado warnings get further broken down by sub-type — Emergency, PDS, Confirmed, Observed, or Radar Indicated — and assigned a severity rank from 1 to 115.
Everything is stored locally in a SQLite database. Nothing is sent from your machine.
StormSync is built for weather enthusiasts, storm spotters, hobbyist meteorologists, and anyone who wants NWS alerts with real speed and detail. It's free, requires no subscription, and is open to anyone who can get NWWS-OI credentials from NWS.